A start-up control apparatus includes a switch, an advanced configuration and power interface (ACPI) controller, a power supply, and a control chip. The switch creates a trigger signal. The trigger signal includes a first falling-edge and a first rising-edge. The control chip includes a control module and a monitoring module.The monitoring module sends a status signal about the power supply to the control module. The control module receives the first falling-edge and sends a second falling-edge to the ACPI controller according to the status signal after receiving the status signal. The ACPI controller sends a control signal to the power supply to enable the power supply to change from a first status to a second status. The control module sends a second rising-edge to the ACPI controller before receiving the first rising-edge when the power supply is in the second status.