Paper analyses student knowledge control and assessment that depends on various objective and subjective factors. Knowledge assessment subjectivity is based on poor knowledge control methods development. Nowadays used computer-based learning and teaching programs and systems are implemented with different knowledge control methods. Offered methods variety asks more attention to organize qualitive knowledge control. Paper describes three main knowledge control models: linear, branch and multiple levels. There are outlined main approaches for control tasks providing during a control based on mentioned models. Paper also shows primary steps for solving knowledge assessment problem: control parameters defining that is made before knowledge control; data, which is being get during control, collecting, analysis and/or processing; mark put after control finishing. Classification of assessment methods is given. It includes two main classes: mathematical and classification methods. Paper gives descriptions for researched models characteristics: the simplest model; model the takes into account answering time; model, based on acquisition levels; line-piece approximation method; models, based on probabilities criteria.