The dissociation of acetone in an intense (10(13)-10(14) W/cm(2)) femtosecond laser field has been investigated. The stepwise nature of the dissociation has been verified by analyzing the time-of-flight mass spectroscopic patterns at different laser intensities. The stepwise nature was interpreted using a quasi-diatomic field-assisted dissociation model and the QCT calculations. Both the experimental identification and the theoretical predictions show that if the laser intensity is gradually increased, the sequence of the primary dissociation is C-C, C-O, and C-H bonds in the acetone ion. The preference of breaking the C-C and C-O bond over the H-elimination of the C-H bond is also the case in the secondary dissociation.