We study the discretization effect on a very popular sliding mode control, the equivalent control based sliding mode control, which has not been addressed before. The investigation is carried out via studying second order linear systems and some interesting dynamic properties are explored and the dynamic behaviors are analysed. Although the analysis is done for second order systems, the conclusions can be extended to higher order systems. To our knowledge, this is the first time the discretization effect on the equivalent control based sliding mode control has been explored.