The modeling and control of batch processes is a challenging and important problem especially when uncertainty and time delay is involved. The uncertainty maybe unadjustable during the practical operation, such the delay tolerability of batch reactors under uncertainty should be figured out to guarantee the operation reliability and safety. To find the maximum time delay that the system can tolerate, a delay tolerability index problem (DTI) is proposed based on the bisection search method combing with dynamic response analysis, where the Nonlinear Control Design package (NCD) is used to optimize the control action. The specific searching procedure and the proposed strategy are also investigated and tested by a batch reactor and a practical polymerization semibatch reactor. All the simulation and analysis results show that the proposed strategy may provide a simple and effective method for the computation and assessment of the maximum tolerable delay for batch reactors under uncertainty. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.