Inverse parabolic problems are the most famous ill-posed problems. Thus using stable inexact numerical methods for approximating these problems, causes a large perturbation. In this paper, we study the problem of determining the source term of the inverse source problem [{partial _t}T(x, t) = kappa, {nabla ^2}T(x, t) + g(t)delta (x-{x^*}), x in {( circ, , 1)^d}, t in ( circ, , {t_f}), ] from the measured data given in the form of [T({x_{measure}}, {t_i}) = {y_i}, , i = 1, 2, ldots, I, ] (additional condition) where d = 1, 2 and [delta ] is the Dirac delta function and (T, g) are the unknown functions. Then, using the statistical spline model and applying Levenberg-Marquardt method, we obtain an approximate solution for quasi solution g=g(t). Finally, to show the priority and accuracy of the introduced method some numerical examples are given.