The invention relates to detection technology field and provides a tool-less tray that is detachably mounted on a casing inner wall. The tray has a plate body and a side wall; at least 3 shaped holes are disposed on the side wall; at least one screw pillar is fixed to the plate body and is configured to be firmly connected to an additional function board. The technical solution provided by the invention is tool-less, realizes fast installation and detachment of tray, realizes fast addition and removal of additional function board in limited space and is convenient to be used.