The invention relates to a spatio-temporal multidimensional safety assessment method for power equipment based on symbolic dynamics and Hidden Markov models, and in particular to sub-link information auditing, time sequence tracking, risk assessment technology and a security situation prediction method based on symbolic dynamics and Hidden Markov models. The advantages of the present invention are as follows: 1. the structural division of a power system can optimize the collection of evaluation factor information; 2. The determining of the information audit points in various links and the improving of the audit information make the power equipment operation status information collection more accurate; 3. The time sequence tracking to the fault information of the audit points in various links considers the historical operation state of the power equipment, which makes the safety assessment more accurate; 4. the operation rules of power equipment can be accurately reflected; and 5. the use of hidden Markov models for the calculation of the prediction of the safety situation and, at the same time, the establishment of a suitable threshold to determine whether there is a safety risk of power equipment improve the accuracy of the assessment of the safety situation.