In this work, a ∼215 nm laser was used to pump mixture gas of Kr and Xe, and a 3680 nm ASE, which is corresponding to the transition of 5d[1/2]1-6p[1/2]1 of Xe, was found. This process was identified as the following: Kr was excited from ground state to 5p[3/2]2 state by absorbing two photon of ∼215 nm, and transferred to 5s[3/2]2 state with ASE emission of 760 nm; Xe(5d[1/2]1) was then populated by near-resonance energy transfer collision with Kr(5s[3/2]2), consequently ASE of 3680 nm was generated. By analyzing the intensity of ASE at 3680 nm, the experiment shows the optimal total pressure and optimal ratio of Kr to Xe. The collision reaction rate constant was evaluated to be 9.6±1.4×10−10cm3s−1 by simulating delay time under different Xe pressures. Under the pressure of 50 torr Kr and 50 torr Xe, gain coefficient of 3680 nm was measured to be 0.035 ± 0.009 cm−1, which make this system a potential candidate for high power middle infrared laser.