Abstract: Number of non-road mobile machinery is relatively smaller than that of motor vehicles, but due to its emission standards starting late, standards formulation and implementation of emission reduction measures are relatively backward．Moreover, due to problems such as a wide power use range, poor operating environment, high mobility, and difficult supervision, resulting in its emission problem has become highly prominent．Particulate matter emissions far exceed motor vehicles．Non-road mobile machinery shoulders an important mission of energy conservation and emission reduction in field of mobile sources in the future, and emission standards upgrading is still an important means to face challenges．From standard system, application scope, emission limits, test cycles, mechanical carborne methods, crankcase and smoke, durability and warranty period, nitrogen oxide and particulate matter control, carborne terminals, and remote monitoring, production consistency management, and in-use compliance monitoring, differences between China IV and European V, EPA Tier 4 standards were comprehensively analyzed, as well as energy technology transformation and internal combustion engine technology development under carbon neutrality background．China's future development trend and suggestions for non-road mobile machinery emission standards were put forward: to further draw on foreign advanced experience in emission test cycles, pollutant limits, durability and warranty, and to follow China's localized and efficient production consistency, in-use compliance, remote monitoring and other management measures．In addition, deficiencies in regulatory scope of current standards should be fully considered, greenhouse gas control should be introduced, and to adapt to diversified development trend of fuels and power systems, application scope of fuels and machinery types should be expanded, striving to achieve standard-led technological development, realizing non-road mobile machinery in future to reduce both pollution and carbon emissions and to promote comprehensive environmental improvement．