The invention relates to the field of oil and gas exploration plugging, in particular to modified cellulose for sol, as well as a preparation method and application thereof. The modified cellulose for the sol is characterized in that a modified group on the modified cellulose is an acrylamide-containing polymeric chain, wherein the content of the acrylamide-containing polymeric chain is 4.5 to 25 weight percent based on the weight of the modified cellulose. The modified cellulose for the sol can be compounded with a crosslinking agent to form gel with relatively strong strength and bonding strength and relatively high temperature resistance and salt resistance, and is favorable for use in oil and gas exploration, and the gelling time can be controlled.