Abstract: Revealing the evolution characteristics of the production-living-ecological space was of great significance for achieving regional sustainable development and optimizing spatial resource allocation. This study, based on intensity analysis models and Markov chain models, explored the spatiotemporal changes and transformation pattern characteristics of the production-living-ecological space in the Beijing-Tianjin-Hebei urban agglomeration, both at the overall level and at the county scale, from 2000 to 2020. Based on the intensity analysis model, the study comprehensively measured the quantitative characteristics of spatial transition and its influencing degree, reflecting the tendencies and inhibitory states of the transformation patterns, and further clarified the transformation patterns of county-level agricultural production space and green ecological space. The study also revealed the stability characteristics of these transformation patterns and discussed their underlying influencing mechanisms. The results showed that: (1) In terms of structure, the primary space structure exhibited transformation characteristics of "significant reduction in production space - expansion of living space - minimal fluctuation in ecological space." The secondary space structure generally showed a trend of "four increases and three decreases," with the most significant reduction in agricultural production space, followed by grey ecological space and green ecological space, while the expansion of rural living space, urban living space, industrial and mining production space, and blue ecological space was relatively prominent. (2) In terms of spatial pattern, the spatial pattern changes of the production-living-ecological space in the Beijing-Tianjin-Hebei urban agglomeration at the county scale showed significant regional differences. The counties with reduced production space were concentrated in the central parts of the urban agglomeration, with the reduction gradually decreasing outward from the center. Living space generally showed a distribution pattern with significant increases in the central and southern regions, decreases in the southeast, and relative increases in other counties. Ecological space generally showed a scattered reduction pattern centered on the central and eastern regions. (3) In terms of transformation patterns, the production-living-ecological space exhibited spatial-temporal differentiation characteristics. The transformation patterns of agricultural production space to living space and production space showed tendencies, while the transformation of green ecological space to production space also showed a tendency. During the study period, the transformation of county-level agricultural production space evolved from slow to rapid development. In the early stage, it mainly shifted to industrial and mining production space and urban living space, while in the later stage, it mainly shifted to industrial and mining production space and rural living space. The transformation trend of green ecological space to agricultural production space and rural living space became more significant in the later stage. (4) The transformation patterns of agricultural production space and green ecological space were relatively unstable. Over the past 20 years, production space and living space continuously squeezed agricultural production space, while the pressure from ecological space on agricultural production space slowed in the later stage. Meanwhile, the transformation trend of green ecological space to living space was evident, especially the transformation to rural living space, which became more significant. The research results provided scientific references for formulating territorial spatial zoning and regulatory measures, as well as for fine management in the Beijing-Tianjin-Hebei urban agglomeration.