The invention discloses a tobacco leaf blocking and control agent for decreasing content of Cd (cadmium) in tobacco leaf and a preparation and use method thereof. The tobacco leaf blocking and control agent is prepared from the following active components in parts by weight: 160 parts of water, 8 to 16 parts of sugar alcohol, 1 to 3 parts of glycerin, 0.2 to 0.4 part of potassium hydroxide, and 2 to 4 parts of surfactant. The preparation method comprises the following steps of (a) adding the sugar alcohol and the glycerin into the water, stirring at the speed of 60 to 100r/min, heating to 70 to 90 DEG C in water bath, maintaining for 5 to 10min, and cooling for standby; (b) adding the surfactant into the cooled solution, stirring at the speed of 60 to 100r/min, and uniformly mixing; (c) adding the potassium hydroxide, and adjusting the pH (potential of hydrogen) value to 7 to 8, so as to obtain the tobacco leaf blocking and control agent. The tobacco leaf blocking and control agent has the advantage that the tobacco leaf blocking and control agent is sprayed by the leaf spraying type, the output of the tobacco leaf is effectively increased, the content of Cd in the tobacco leaf is obviously decreased, and the quality of the tobacco leaf is improved.