Strain engineering is proposed to be an effective technology to tune the properties of two-dimensional (2D) transition metal dichalcogenides (TMDCs). Conventional strain engineering techniques (e.g., mechanical bending, heating) cannot conserve strain due to their dependence on external action, which thereby limits the application in electronics. In addition, the theoretically predicted strain-induced tuning of electrical performance of TMDCs has not been experimentally proved yet. Here, a facile but effective approach is proposed to retain and tune the biaxial tensile strain in monolayer MoS₂ by adjusting the process of the chemical vapor deposition (CVD). To prove the feasibility of this method, the strain formation model of CVD grown MoS₂ is proposed which is supported by the calculated strain dependence of band gap via the density functional theory (DFT). Next, the electrical properties tuning of strained monolayer MoS₂ is demonstrated in experiment, where the carrier mobility of MoS₂ was increased by two orders (~ 0.15 to ~ 23 cm²·V^-1·s^-1). The proposed pathway of strain preservation and regulation will open up the optics application of strain engineering and the fabrication of high performance electronic devices in 2D materials.