Abstract: The analysis of the general Cournot model shows that the reason for strengthening, instead of dissecting, the Bertrand s paradox lies in that its assumed preconditions are far away fromthe real economic conditions. For this reason, the assumed preconditions were modified as follows: the cost of oligopoly manufacturers entering a professional market increases continuously and the marginal cost of products does not equal zero. Through rigorous mathematical deduction, the following conclusionswere drawn,i.e., the numberof oligopolies is limited by the increasing cost-of-entry, the market capacity is decreased by the existence of the marginal cost, and oligopolistic competition will not result in perfect competition easily.