A real-time measuring circuit for neutron (1 MeV equivalent) fluence measurement is presented in this paper. The discrete bipolar junction transistor (BJT) is used as the neutron fluence monitor, according to the change in the reciprocal of the current gain varying linearly with the neutron fluence. However, a measuring error cannot be neglected due to the temperature dependence of the BJT current gain. By analyzing the temperature parameters of the current gain equation, the analytic relation between current gain and temperature is obtained, and the correction method of the measurement error caused by the change in temperature is represented. The experimental results show that the corrected measurement error decreases obviously in a larger temperature range. As a result, the measurement accuracy is improved evidently.