A Tm:YAP laser pumped Mid-IR solid-state laser is reported. First, the Tm pulse laser is described, the structure of laser cavity is optimized by analyzing the experiment results. Then, the appropriate type of YAP laser cavity of ZnGeP 2 OPO pump is confirmed, and obtained 2 μm pulse laser output is ideal. Mid-IR solid state laser is composed of optimized Tm:YAP laser pump optical parametric oscillator (OPO). Finally, more than Watt-level output power at 3～5 μm is obtained.