Eclipsing binary (EB) systems showing double lines in their spectra are excellent sources of knowledge about structure and evolution of stars. The analysis of photometric and spectroscopic data in such double systems provides very accurate values for the absolute properties of both stars, as well as clues about their internal structure, their formation process and the possible existence of other bodies altering their motion. V402 Lac is a V=6.7 mag binary system with two B9 type stars at a distance of 240 pc from the Sun, classified as an Algol-type EB since Hipparcos observations. In our work we are using light curves and radial velocity data in order to obtain the parameters of the binary system through an analysis with the Wilson-Devinney (WD) code. The first results, using independently the two types of data, show a clear discrepancy in some orbital parameters, which is also reproduced by new observations. Our study also revealed the existence of apsidal movement in the system, and all the times of minima are being used in order to characterize it through an O-C diagram. We are dealing with a very interesting EB with no solution for the moment. The photometric observations scheduled for late 2010 can be decisive to solve the orbit of the system and then be able to obtain accurate values of the physical properties of the stars.