We revisit the quantum discord, quantum entanglement and local hidden variable models in quantum mechanics, and present a kind of understanding of quantum states from the view of correlations given by the probability distributions of local measurements outcomes.Keywords Quantum discord · Quantum entanglement · LHV modelThe correlations among the subsystems of a multipartite system play significant roles in many information processing tasks and physical processes. The types of correlations existed in a system depend on the state of the system. The evolution of the states results in the evolution of the correlations. It is of importance to learn and classify the states according to the correlations contained in a system. Physically, to get information from a system one needs to measure the system. Hence the kind of correlations in a state can be determined in terms of the probability distributions of the measurement outcomes. By revisiting the quantum discord, quantum entanglement and local hidden variable models in quantum mechanics, we attend to present a kind of understanding of quantum states from the view of correlations.Let us begin with the classical correlations between two random variables. If X is a random variable which has value x with probability p(x), then the information content S(X) of X is defined to be the information you would gain if you learned the value of X, given by the Shannon entropy,S is a function of the probability distribution of the values of X. The information is maximum when our prior knowledge of X is minimum. If X can take N different values, the information content (or entropy) of X is maximized when the probability distribution p is flat, with every p(x) = 1/N . And the maximum information which could in principle be stored by a variable which can take on N different values is log 2 (N ). When X can take two values with