The invention discloses a low-sensitive type polycarboxylic acid slump retaining agent and a preparation method thereof. A structural formula of effective components of the low-sensitive type polycarboxylic acid slump retaining agent is shown as below (please see the formula in the description). The low-sensitive type polycarboxylic acid slump retaining agent can effectively reduce sensitivity of age flowing of concrete, and the phenomena that due to the fact that the mixing amount of the polycarboxylic acid slump retaining agent is too high or too low, after standing is conducted on the concrete, bleeding (even segregation) occurs, or the flowability is too poor can be effectively avoided.