Engineering geological evaluation is an important work to ensure the safety of major engineering construction. Facing the planning and construction needs of major projects in the new era, this paper puts forward the connotation and objectives of geological safety evaluation. Taking the railway engineering construction in plateau mountainous region as an example, the method, workflow and application examples of geological safety evaluation are discussed. Some conclusions are as follows: different stages of railway construction correspond to different evaluation scale. The regional scale, less than 1：50000, can be used in the planning stage, which is based on the evaluation of regional crustal stability, aiming to qualitatively give the railway corridor safety or suitability. In the feasibility study stage, the key segment scale, such as 1：10000~1：25000, can be used for evaluation of the engineering geological stability, so as to further determine the poor geological combination and major geological risks, and guide route optimization. In the design stage, the site scale such as 1：2000 is suitable, which is to focus on specific geological risks or engineering rock mass stability issues. Special evaluations are carried out according to relevant technical standards and thematic analysis and research. In general, as the geological risk degree goes from high to low, the corresponding geological safety degree goes from low to high. According to the level of geological risk and the difficulty of prevention and control, the geological safety evaluation results can be divided into four degrees including safe, subsafe, relatively unsafe and unsafe. The segments, where safety requirements cannot be guaranteed under current technical conditions, should be avoided for site selection. It is suggested to incorporate geological safety evaluation into the necessary processes of national engineering construction management, and speed up the formulation of relevant technical standards.