The invention provides a method for expanding the HCCI combustion load on the basis of a cylinder pressure sensor, and belongs to the technical field of internal combustion engines. The method includes the following steps that a crank corner phi[i] is detected through a cam shaft position sensor and a photoelectric encoder; an ECU calculates the cylinder instantaneous volume V[i] corresponding to the crank corner phi[i]; a cylinder pressure sensor detects the inside-cylinder pressure P[i] corresponding to the crank corner phi[i]; the ECU calculates the average indication pressure IMEP_i corresponding to the crank corner phi[i]; the ECU gives the load upper limit detonation boundary upper limit value IMEP_max and the load lower limit misfire boundary lower limit value IMEP_min; when an engine works according to the NVO strategy, the load of the engine is increased, and when the measured IMEP_i is higher than the IMEP_max, the ECU regulates the NVO strategy into the LEVC strategy; and when the engine works according to the LEVC strategy and the measured IMEP_i is lower than the IMEP_min, the ECU regulates the LEVC strategy back to the NVO strategy. The valve gas distribution phases are regulated through inside-cylinder pressure signals fed back by the ECU, and according to different load ranges of different gas distribution phases, HCCI stable combustion is achieved, and meanwhile the HCCI combustion load range can be expanded.