We present first ground-based multi-colors photometric study of an eccentric, double-lined eclipsing binary system V402 Lac. Analyzing the data obtained in this study together with earlier studies in the literature we derived the orbital and physical parameters of this detached binary system of considerable interest. Derived physical parameters of the components are as follows; My = 2.86 0.06M circle dot,R-1 = 2.61 +/- 0.04 R circle dot, R-2 = 2.16 +/- 0.034,14 = 98 5 L circle dot and L-2 = 69 3 L circle dot. Using the newly obtained parameters the distance of the binary is determined to be 262 33 pc. In addition, the system show apsidal motion whose period is determined to be 213 years. A possible third star (M-3 sin i = 1.9 M circle dot) orbiting the binary system in an eccentric orbit (e = 0.23) with an orbital period of 20.5 years has been detected in this study with M.