Abstract: We reported a continuously and passively mode-locked Nd∶YVO4 crystal picosecond oscillator based on 888 nm semiconductor pumped. We used the way of thermal excitation to improve the thermal performance of the laser, as well as increase the average output power and the single pulse energy of the modelocked oscillator. We achieved the starting and maintaining of the laser mode-locking by semiconductor saturable absorber mirror(SESAM). Under the absorbed pump power of 60 W, the maximum output power of 15 W at 53 MHz repetition rate was obtained, and the optical-to-optical efficiency of 24% was achieved. The pulse width was measured at 45 ps when the output power was 15 W.