A positive electrode active material, a positive electrode plate, a secondary battery, and a power consuming apparatus are provided. The positive electrode active material includes (i) secondary particles and (ii) single-crystal or quasi-single-crystal particles. The secondary particles are mainly formed by aggregating primary particles and the secondary particles further include an M1 element. The M1 element includes a transition metal element other than iron. A mass content of the M1 element is X1 based on a total mass of the secondary particles, where 500 ppm≤X1≤5000 ppm, and optionally, 800 ppm≤X1≤2000 ppm. The single-crystal or quasi-single-crystal particles include an Ma element. The Ma element includes a transition metal element other than iron. A mass content of the Ma element is X2 based on a total mass of the single-crystal or quasi-single-crystal particles, where X2 is less than X1.