The invention provides a three-dimensional modified polyester fiber mattress which comprises two bases which are spliced to form a whole, wherein the mattress is arranged on the upper base; and eight groups of painted legs are symmetrically arranged on the lower surface of the lower base. According to the three-dimensional modified polyester fiber mattress, the conventional mattress spring structure is changed and replaced by the three-dimensional modified polyester fibers; the mattress is attractive and good in ventilation and air permeation effects, can be washed completely, has high supporting force (supporting 40 pieces of functional wires per square centimeter), high elasticity and high antifouling and dampproof performance, is soft and comfortable and can physically resist bacteria and mildew; the mattress supplies high balance supporting force to the body of a user, so that the use stability is improved; and the mattress is relatively healthy, sanitary and environment-friendly, can be used for multiple times without being replaced, meets the age requirement and is suitable for different age groups.