The invention provides a modified inorganic waterproof plugging material which comprises the following components in parts by weight: 100 parts of cement, 0.5-3 parts of water reducing agents, 1-5 parts of diphenylmethane diisocyanate, 0.1-0.6 part of early-strength agents and 0.05-0.25 part of reaction regulating agents, wherein the cement comprises silicate cement and sulphate aluminium cement, the weight of the sulphate aluminium cement accounts for 0%-40% of the total weight of the cement, the early-strength agents are one of lithium salt or potassium hydroxide or mixtures of two lithium salt and potassium hydroxide in any proportion, the water reducing agents are naphthaline water reducing agents or polycarboxylic acid water reducing agents, and the reaction regulating agents are one of triethylenediamine, N-methyl-N'-ethoxyl piperazine or potassium octoate or mixtures of more than two of triethylenediamine, N-methyl-N'-ethoxyl piperazine and potassium octoate in any proportion. The modified inorganic waterproof plugging material has the advantages of long mixing time, good volume stability, difficult cracking, enhanced later-strength stability and the like, and is suitable for large-volume construction and is suitable for the rescue plugging of a waterproof anti-permeable project.