Abstract: In order to study the influence of hybrid fibers on the mechanical properties of pumice light aggregate concrete, six groups of pumice light aggregate concrete test blocks with a polypropylene fiber content of 0.6 kg/m~3 and a change of cellulose fiber content were tested for cube compression and splitting tensile. The results show that the compressive strength and splitting tensile strength of the cube first increase and then decrease. The splitting tensile strength increases significantly, and the optimal dosage is 3.2 MPa, which is 77.8% higher than the benchmark group. Fiber incorporation can effectively prevent the development of cracks and play a role in strengthening and toughening. The optimal content is 0.9 kg/m~3 of cellulose fiber with polypropylene content of 0.6 kg/m~3 and cellulose fiber. At this time, the tensile-compression ratio is increased by 57.7% compared with the benchmark group, which significantly improves its brittleness. At the optimum content, the early strength ratio at 3, 7, 14 days is increased by 25.2%, 20.7%, and 15.6%, respectively. According to its mechanical properties, a calculation formula for the 28-day cube compressive strength of natural pumice stone lightweight aggregate concrete is proposed and compared with other formulas for verification. The BP neural network is used to predict the 28-day intensity, and the prediction data is used to verify the compressive strength calculation formula, and the verification results are good.