This paper analyzes the first obtained four-color light curves of V396 Mon using the 2003 version of the W-D code. It is confirmed that V396 Mon is a shallow W-type contact binary system with a mass ratio q=2.554(+/-0.004) and a degree of contact factor f=18.9%(+/-1.2%). A period investigation based on all available data shows that the period of the system includes a long-term decrease (dP/dt=-8.57x10^-8^days/yr) and an oscillation (A3=0.0160day, T3=42.4yr). They are caused by angular momentum loss and light-time effect, respectively. The suspect third body is possibly a small M-type star (about 0.31 solar mass).