The invention relates to a table-chair lifting device easy for height adjustment. A table-chair outer support leg is provided with connection holes corresponding to connection holes reserved on a table-chair inner support leg, a bolt can be inserted into two mutually corresponding connection holes, the position of the table-chair inner support leg which is lifted up or lowered is fixed through the bolt, the bolt is hinged to the table-chair outer support leg, a bolt return spring is mounted between the bolt and the table-chair outer support leg, a head of the bolt can penetrate into one connection hole of the table-chair outer support leg and penetrate into the corresponding connection hole on the table-chair inner support leg, the head of the bolt is kept being inserted into the corresponding connection holes of the table-chair inner support leg and the table-chair outer support leg under the action of the bolt return spring, and the a lower contact face, in contact with the corresponding connection hole, of the head of the bolt is a sloping face. The table-chair lifting device has the advantages of simple structure, economization, practicality, easiness for adjustment, high efficiency, safety, reliability and low cost.