The invention discloses a multifunctional water well packer which comprises an external working barrel and a central pipe arranged in an inner cavity of the external working barrel. The outer portion of the middle segment of the external working barrel is sleeved with packing pieces, at least one well washing hole communicated with an annulus between the working barrel and the central pipe from the outer side of the external working barrel is formed in the position, above the packing pieces, of the external working barrel, an upper pressing control type well washing mechanism is arranged in the annulus between the central pipe at the positions of the well washing holes and the external working barrel, and an internal anchoring mechanism is arranged at the position, above the upper pressing control type well washing mechanism, of the external working barrel. A setting mechanism is arranged below the packing pieces, and a slip anchoring mechanism is arranged below the setting mechanism. The internal anchoring mechanism can prevent well washing liquid pressure from unsetting the packer. The slip anchoring mechanism can avoid packer wriggle caused by fluctuation of water injection pressure. The upper pressing control type well washing mechanism can achieve reverse circulation well washing.