There exists a performance limitation in a pulsed Geiger-mode avalanche photodiode laser ranging system because of the echo intensity random fluctuation caused by turbulence effects. To suppress the influence of turbulence effects, we present a cumulative pulse detection technique with the ability to achieve improved cumulative probabilities and range accuracy. Based on the modulated Poisson model, the cumulative probabilities, range accuracy, and their influencing factors are investigated for a cumulative Q-switched laser pulse train. The results show that the improved cumulative probabilities and range accuracy can be obtained by utilizing cumulative pulse detection, with the condition that the echo intensity is 10, the echo pulse width is 10 ns, and the turbulence degree is 3, the target detection probability increases by 0.4, the false alarm probability decreases by 0.08, and the accuracy and precision increase by 46 cm and 27 cm, respectively.