The invention discloses an adjustable spraying head for a garden agent spraying device. The spraying head comprises a liquid inlet pipe and a spraying head body. A liquid flow channel is arranged on the liquid inlet pipe. A first groove is provided on the spraying head body. A tapered spraying head core is arranged on the spraying head body. A spray hole sheet is arranged on the upper part of the spraying head body. A spray hole is provided at the spray hole sheet. A spraying head cap is arranged on the upper part of the spray hole sheet. The spraying head cap is threadedly connected with the spraying head body. A liquid outlet hole is provided on the spraying head cap at a place corresponding to the spray hole. The spraying head cap is also provided with a slide groove. A slide piece is arranged at the slide groove. A flow rate hole is arranged on one side of the slide piece, and a projection which can bear against the end of the spraying head cap is arranged on the other side of the slide piece. The spraying head provided by the invention has the following advantages: with the slide piece added at the spraying head cap, spray hole flow rate control can be realized through the relative positions of the flow rate hole on the slide piece and the spray hole. The spraying head also has the advantages of simple structure and convenient application.