Tm∶YAP/YAP composite laser crystal boule with diameter more than 40 mm is directly grown by induction heating Czochralski method through improving the thermal field, changing raw materials, and secondary welding growth. The boule shows no visible cracks, good optical homogeneity and uniform residual stress. For the cylinder part of the boule, the length of the YAP segment is 21 mm, and the length of the Tm∶YAP segment is 44 mm. Under the irradiation of green laser and He-Ne laser, there is no any scatters and bubbles observed at the composite interface. The interference fringes on both sides of the composite interface are basically continuous, and the wavefront difference of transmission is very small. Two composite Tm∶YAP/YAP crystal rods with size of 5 mm×30 mm each and YAP segment without doping at the end of 4 mm long were prepared from the boule. Both rods show excellent optical quality. The laser performances of the rods were tested on 1 940 nm solid-state laser. By single end pump of laser diode, the laser output of 42.8 W is achieved when the input pump power is 117.7 W. Compared with the non-composite laser crystal, the composite Tm∶YAP/YAP crystal shows higher output power, higher conversion efficiency and better beam quality.