Abstract One-layer particle level set (OPLS) has been developed by using Lagrangian particles that are employed to correct both advection and re-initialization procedures of the level set function. In which, a level set function is utilized to smooth physical properties of the interface, while one-layer Lagrangian particles are used to track the interface directly. This method exhibits excellent mass conservation properties compared to the LS method. As a special aspect, the OPLS method enables management of merging and stretching of interface in an effective way. This capability is similar to the particle level set (PLS) method. However, the new approach of the OPLS method offers a more straightforward technique. This approach is validated with classical benchmark test cases, such as the long term advection of a circle, rotation of a slotted disk, single vertex in a box, merging and separating of circle. The results from the proposed method show good agreement with the numerical experiments published results and the OPLS method is verified to be highly reliable and accurate.