The invention discloses a fatigue performance evaluation method for connecting attachment weld of an orthotropic steel bridge deck top plate and a longitudinal rib. The method comprises the following steps of: S1, performing static loading on test pieces to be tested, testing and recording static load stress responses [epsilon]0 (D1) and [epsilon]0 (D2); S2, performing fatigue loading on the test pieces to be tested, testing and recording [epsilon]1 and [epsilon]2, and recording the fatigue failure lives Ni of the test pieces to be tested; S3, calculating the nominal stress amplitude [delta][sigma]ns of the attachment weld according to the static load stress response [epsilon]0 (D1) and [epsilon]0 (D2), and calculating the hot spot stress amplitude [delta][sigma]hs of the attachment weld; S4, converting the [delta][sigma]ns and the [delta][sigma]hs into an equivalent nominal stress amplitude [delta][sigma]'ns and an equivalent hot spot stress amplitude [delta][sigma]'hs under M-times service lives respectively; and S5, respectively averaging the [delta][sigma]'ns and the [delta][sigma]'hs of each piece to be tested to obtain the fatigue strength grade of the orthotropic steel bridge deck top plate and the longitudinal rib fatigue details specified in the specification, and performing comparative analysis on the fatigue strength grade. The test method can be used for determining the fatigue strength of the connecting attachment weld of the orthotropic steel bridge deck top plate and the longitudinal rib, and evaluating the fatigue strength of the attachment weld more accurately.