In order to save the usage of system resources and adapt the variation of plant state, this study first proposes a novel stochastic‐sampling‐based adaptive event‐triggered scheme (AETS). Second, in the framework of time‐delay systems, the closed‐loop control system is modelled as a class of delayed stochastic systems where time‐delay is distributed in some intervals with probability. Then, by employing stochastic analysis tool and Lyapunov stability theory, a stability criterion for this class of delayed stochastic systems is established to ensure that the system possesses stochastically asymptotic stability with an disturbance attenuation performance. Also, a co‐design of parameter matrices of the state‐feedback controller and the stochastic‐sampling‐based AETS is implemented. Third, based on the obtained co‐design condition, a convex optimisation algorithm for the tradeoffs between disturbance attenuation performance and resource utilisation of the closed‐loop control system is further developed. Finally, the effectiveness and feasibility of the proposed control strategy are illustrated by two numerical examples of adaptive event‐triggered control for networked control systems under stochastic sampling.