A tool-free fixation structure for a data storage device includes: a tray, a front end, center and rear end thereof being respectively formed with a position limiting portion, pressing portion, and elastic propping portion, an accepting space being formed between the position limiting portion and elastic propping portion, two propping sheets being respectively disposed on two sides of the elastic propping portion, and positioning columns being disposed on the tray at a lower side of the accepting space, an outer threaded portion being disposed on a circumference of each positioning column; a data storage device, threaded holes adapted to accept the corresponding positioning columns therein, being on a lower side thereof, an inner threaded portion being disposed in each threaded hole, thereby allowing the propping sheets to press against the data storage device, and achieving a tight engagement of the inner threaded portions with the corresponding outer threaded portions.