To address the polarization dependence or complex structure of common optical modulators,this paper proposes a controllable optical pulse modulator based on optofluidics.The continuous light is converted into digital pulse signal by using a microfluidic optical switch,which based on the discrete droplets generated by T-junction and the principle of total internal reflection,and the width and frequency of the optical pulse can be modulated by adjusting the length and generation rate of the droplets.The proposed microfluidic optical pulse modulator has the advantages of simple structure,low insertion loss,high extinction ratio and easy integration.The flow field and optical field characteristics of the microfluidic optical pulse modulator are analyzed and its structure is optimized. The results show that the extinction ratio of the optical pulse modulator is 17.74 dB and the insertion loss is 0.49 dB.