Abstract: Drilling in underground mine is a technical means to obtain geological data and eliminate safety risks in daily production of coal mine. But at the present, most of holes drilled during coal production do not have trajectory measurement, leading to accidents resulting in poor safety measures due to the wrong geological data. In order to solve this problem completely, this paper introduces the principle of drilling trajectory measurement and develops a set of electromagnetic wave wireless measurement system based on AHRS. The system has the characteristics of low cost and convenient application, and it can also meet the requirements of wireless measurement. Through the underground industrial test, it has been proved that the measurement system for the drilling trajectory can effectively complete the measurement of the drilling trajectory and improve the drilling efficiency.