The invention discloses an installation in-place detection mechanism of an injector flange used for an injection pump, comprising a slide rail part (4), an injector flange groove (7), a slide bar (6) and a position detection part, wherein, the slide rail part (4) is fixed in the injection pump, and a slide rail groove is arranged in the slide rail part (4) along the longitudinal direction; the injector flange groove (7) is arranged at one end of the slide rail part (4), and is communicated with the slide rail groove; the slide bar (6) is arranged in the slide rail groove of the slide rail part (4) slidably, and has a first slide position and a second slide position, wherein, in the first slide position, the first end of the slide bar (6) is positioned in the injector flange groove (7); and in the second slide groove, the first end of the slide bar (6) is contacted with the flange of the injector, and the second end of the slide bar (6) extends out of a slide rail; and the position detection part is arranged at one end of the slide rail part (4), and is triggered by the second end of the slide bar (6) to provide an indication signal when the slide bar (6) is positioned at the second slide position. By the mechanism provided by the invention, whether the injector flange is installed in place or not can be simply and conveniently detected.