Its characteristic is that in specific work, both sides demonstrate and explain while practicing and learning. If there are problems, you can ask questions, supplement and correct them on the spot, and you can also find out the shortcomings and irrationalities in previous work operations in the interaction, so as to improve them. Also called "workplace training".

The advantage of OJT is that training can be carried out on the job without delay, and neither side needs to invest extra time, energy and expenses. In addition, OJT can closely link training with practical work and form the interaction between teaching and learning. Its disadvantage is that if the person in charge of training is not good at educating others, the result will be unsatisfactory, and once the work is busy, it is often impossible to give a careful explanation.

It should be emphasized that OJT must be based on making plans and goals in advance. Otherwise, simply letting employees "learn knowledge and skills while working" is not called OJT.