This paper explores the influence of video types and knowledge types on cognitive load in college video teaching through experiment. The results show that: the main effect of video types show a significant difference in extraneous cognitive load and germane cognitive load, but do not show a significant difference in intrinsic cognitive load; The main effect of knowledge types show significant differences in intrinsic cognitive load, extraneous cognitive load and germane cognitive load; The interaction effect of video types and knowledge types showed significant difference in extraneous cognitive load and germane cognitive load, but do not show significant difference in intrinsic cognitive load. When designing teaching videos, attention should be paid to: in order to reduce extraneous cognitive load and improve germane cognitive load, gesture clues and proxy answers should be added when designing teaching videos; Compared with procedural knowledge, declarative knowledge is more suitable for teaching with teaching videos; For learning that emphasizes procedural knowledge, it is recommended to use vicarious interaction videos.