In solving algebraic problems, there are two possible student answers, namely right or wrong. However, the correct answer is not necessarily through a process that is in accordance with the actual concept or what is called pseudo. Errors and pseudospheres made by students when solving algebraic problems can be grouped into conceptual errors and procedural errors. Conceptual errors and procedural errors are mistake that cannot be ignored in the learning of prospective mathematics teachers. Teachers need to identify these errors in order to provide corrective or corrective instructions. The purpose of this study was to identify and characterize the types of student errors in solving algebraic problems and to describe students' conceptual and procedural errors in solving algebraic problems. The design used for this research is a mixed method. There are two stages in this research. The first stage, identifying and characterizing the types of student errors in solving algebraic problems. The second stage, describes students' conceptual errors and procedural errors in solving algebraic problems. The subjects of this study were 92 students of the Mathematics Education Study Program at a university in South Sulawesi. The results of the study show that conceptual errors in algebra are caused by misconceptions about certain concepts, making equivalence between several concepts without regard to conditions, and ambiguity in interpreting mathematical symbols. Meanwhile, procedural errors are more errors at the completion stage due to the generalization of the rules.