The invasive irradiation temperature measurement was applied to trace the process of thermal interaction between lasers and bio-tissues. Portable Infrared thermal detector has inside LD red introductive light and can make a sound when aiming at an object. The minimum measured diameter is 2.5 mm at the distance of about 25 mm. The changes of the target's temperature rise are general reveal of both the laser parameters and the optical and thermal properties of the bio-tissue,which are closely relative to the final therapy effect. Experimental results included the real thermal responses of several tissues under single ruby laser pulse and CW CO₂ laser. The thermal response difference was also discussed with variable duration time,temperature rise peak and rise time.