Direct methods for plastic design of limit states of structure include limit and shakedown analysis. These methods state the design problems as mathematical optimization problems [1-3]. In this work we consider a model of stochastic programing to compute limit and shakedown loads of 2D frame structures under uncertainty of constant and time variant loads. We restrict our investigation to the case of normal distributed loading, strength is lognormal distribution. Based on upper bound theorem of plastic theory, we formulate problem as a nonlinear program with probabilistic constraints and then convert into an equivalent deterministic nonlinear program. The solution is obtained by a Newton-Type algorithm for nonlinear programming. The numerical investigates show that the load factor decrease strongly if we consider uncertain property of load.