In this paper, breakup of liquid jet is simulated using smoothed particle hydrodynamics (SPH) which is a meshless Lagrangian numerical method. For this aim, flow governing equations are discretized based on SPH method. In this paper, SPHysics open source code has been utilized for numerical solutions. Therefore, the mentioned code has been developed by adding the surface tension effects. The proposed method is then validated using dam break with obstacle problem. Finally, simulation of two-dimensional liquid jet flow is carried out and its breakup behavior considering one-phase flow is investigated. Length of liquid breakup in Reyleigh regime is calculated for various flow conditions such as different Reynolds and Weber numbers and the results are validated by an experimental correlation. The whole numerical solutions are accomplished for both Wendland and cubic spline kernel functions and Wendland kernel function gave more accurate results. Effect of fluid viscosity is investigated in the breakup length of the fluid as well. The accomplished modeling presented that smoothed particle hydrodynamics (SPH) is an efficient method for simulation of liquid jet breakup phenomena.