The invention is applicable to the technical field of lithium ion batteries, and provides a charging method and device of a lithium ion battery and terminal equipment. The method comprises the following steps: obtaining a first relation between the remaining electric quantity and an open-circuit voltage of the lithium ion battery, a second relation between the remaining electric quantity and the ohmic internal resistance of the lithium ion battery, and a third relation between the remaining electric quantity and a polarization voltage of the lithium ion battery; and performing polynomial fitting on the first, second and the third relations according to the estimated temperature of the lithium ion battery, obtaining the estimated temperature of the lithium ion battery, and performing charging current optimization according to the estimated temperature to obtain a charging current sequence with the minimum battery temperature increment after optimization. According to the invention, thetemperature increment of the battery in the charging process is relatively low, the charging time is shortened, the influence of temperature rise on the service life of the battery in the charging process is reduced, and the charging efficiency is improved.