This article was devoted to the stiffness modeling of parallel robot Tripteron, which contains 3 separate legs directed along axes X, Y and Z. Two different techniques, Virtual joint modeling(VJM) and Matrix structural analysis(MSA) were applied in order to obtain the desired elastostatic model of the robot. Cartesian stiffness matrices were determined in a semi-analytical manner, corresponding deflections of the end-effector under external loads were represented in the form of deflection maps. Both approaches were analyzed and compared according to the computational cost and difference between results.