In the present study, a new method was proposed for the preparation of uniform size and spherical shape microparticle in a microchannel. For this purpose, external gelation was selected based on gravitational driving force. A three-way microchannel was built and the effect of different parameters including; concentration, surfactant and flow rate on size and morphology of microparticle were investigated. The experimental results show that by changing these parameters, it is possible to reach a suitable condition for producing microparticles. Three levels of each parameter were examined to find the best condition based on the size and morphology. Selection criteria are uniform size and morphology. Size and standard deviation and sphericality of microparticles in the best condition are 0.42 mm, 0.01 mm and 96%, respectively. On the other hand, results show that by changing the surface tension of oil and CaCl2 solutions, the microparticle shape can become elongated-shaped, tail-shaped and spherical. This method can also be used for other polymers, only if the suitable conditions such as concentration and flow rate of phases to be found.