The barium release experiment is an effective method to explore the near-earth environment and to study all kinds of space physics processes.The first space barium release experiment in China was successfully carried out by a sounding rocket on April 5,2013.This work is devoted to calculating the release effciency of the barium release by analyzing the optical image observed during the experiment.First,we present a method to calibrate the images grey value of barium cloud with the reference stars to obtain the radiant fluxes at different moments.Then the release efficiency is obtained by a curve fitting with the theoretical evolution model of barium cloud.The calculated result is basically consistent with the test value on ground.