Abstract: The　emitting　mechanism　of　the　fluorescent　lamp　is　studied　and　two　kinds　of　high-pressure cold-start　circuits　are　designed　to　rekindle　the　waste　fluorescent　lamps，which　breaks　the　traditional　electronic　ballast　hot　start　mode.The　main　features　of　the　restart　mode　are　instant　starting，no　flash，on　influence of　frequent　switching　on　the　lamp　life.