The levels of immunofluorescence assay (FA), indirect immunofluorescence assay (IFA), and enzyme-linked immunosorbent assay (ELISA) in the dynamic detection of the avian leukosis virus subgroup J (ALV-J) into DF1 cells were compared and evaluated. The rNX0101 strain of ALV-J was inoculated into DF-1 cells at three different concentrations (1×10², 1×10³, 1×10⁴ TCID₅₀). Results showed that with ELISA, the rNX0101 strain was first detected on the 3^rd day at a concentration of 1×10² TCID₅₀ and on the first day at concentrations of 1×10³ and 1×10⁴ TCID₅₀. FA failed to detect the positive cells until the 3^rd day after inoculation at a concentration of 1×10² TCID₅₀. IFA detected the positive cells in the culture at all concentrations from the 1^st day to the 6^th day, except for the 1^st day, when used at a concentration of 1×10² TCID₅₀. The ratios of the positively infected cells highly conformed to the trend in inoculation concentration on the same days, and IFA exhibited higher sensitivity than did FA and ELISA in the dynamic detection of ALV-J.