The invention provides a multifunctional cap and a cap assembly. The multifunctional cap and the cap assembly are used for solving the technical problem that auxiliary tools of old people are single in function in the prior art. The multifunctional cap comprises a cap body and a warning device arranged on the outer side face of the cap body; the warning device comprises colorful dynamic display lamps and auxiliary reflective stripes, wherein the colorful dynamic display lamps and the auxiliary reflective stripes are arranged at intervals; the colorful dynamic display lamps extend in the peripheral direction of the cap body to form an annular structure, and the auxiliary reflective stripes extend in the peripheral direction of the cap body to form an annular structure.