In this work, we applied the classical numerical method of the secant in the p-adic case to calculate the cubic root of a p-adic number $a\in\mathbb{Q}_{p}^{\ast }$ where $p$ is a prime number, and this through the calculation of the approximate solution of the equation $x^{3}-a=0$. We also determined the rate of convergence of this method and evaluated the number of iterations obtained in each step of the approximation.Computing both the cubic root and other roots of a p-adic number is useful both for their theoretical values as for their theoretical applications in the field of theoretical computer science and cryptography.