Ensuring the technical and economic consistency of carrying out a project with the contract that binds it to its client, in particular by respecting the deadlines set, the budget set and the technical specifications defined is the main objective of the project manager. However, he is limited in his freedom of choice by a certain number of constraints notably in terms of time, time and resources to carry out his project. The aim of this article is to design an algorithm for planning projects subject to a resource constraint. The methodology used is based on the theoretical and methodological approaches proposed in the field to allow the project manager to achieve its objectives including in particular the critical path and critical chain method, mathematical programming as well as a multitude of heuristics and meta heuristics. We propose a modification to the parallel parallel heuristic method and develop a planning algorithm that we have computerized. The result obtained in this article is the development of a realistic project implementation plan which minimizes its duration of realization in the event of a limitation of the allocated resources. The major innovation of this work is the proposed tools which allow the project manager to be able to simulate the impact on the duration of realization of different scenarios of resource allocation.