The present study has been conducted to develop a heat pipe heat exchanger for middle-high temperature ranged from 300 to $600^{circ}C$. Heat transfer rate, overall heat transfer coefficient and temperature effectiveness were investigated using a heat pipe heat exchanger with Dowtherm A as working fluid. Theoretical analysis was also conducted, and the followings were obtained: (1) Heat exchange rate increased as waste gas temperature supplied to evaporator and frontal velocity in condenser increased, (2) Overall heat transfer coefficient increased by $3{sim}7\%$ as frontal velocity in evaporator and condenser increased, (3) Temperature effectiveness was about $30\%$ in evaporator and was about $40\%$ in condenser, (4) Heat recovery rate was about $38\%$, (5) Pressure drop did not exceed $8;mmH_{2}O$ under the running condition of $1{sim}3Nm/s$, (6) Simulation results were corresponded with experimental results.