The focusing precision of the linear Fresnel collector has an important effect on the photothermal efficiency. Moreover, the partial hot spot caused by the partial focus of the concentrator causes an unbalanced expansion of the absorber, which causes severe damage to the collector's structure. Therefore, it is crucial to analyze the concentrating error of the collector. According to the characteristics of the linear Fresnel heat collecting system, the main factors affecting the light-gathering precision of the Fresnel collector are discussed through mechanism analysis. All the factors are analyzed and simulated by MATLAB software, and it is concluded that the main factors that cause the concentration deviation of the collector are the north-south arrangement deviation of the linear Fresnel mirror field, dynamic displacement deviation of the reflection center of the primary mirror, and dynamic variation of the light path of the reflected light. The concentrated light deviation caused by the north-south deviation of the mirror field layout is normally distributed at noon and varies with the latitude. Meanwhile, the effect of the dynamic displacement deviation of the reflection center of the primary mirror on the focusing precision is greater in the morning and evening, and it is asymmetric in the morning and afternoon with the maximum error approaching 0.08°. The influence of light path variation of the reflected light on the concentrating error is mainly reflected in the annual time axis. Through simulation analysis and field testing, the linear compensation algorithm was used to compensate the target tracking angle of the collector's primary mirror. After the compensation, the maximum concentration error of the heat collecting system was less than 0.06°.