It's my first time to build a power supply(flyback),which operate in 1MHz.
so I should select the Inductors (Coils),which Self-Resonant Frequency >1MHz
Then I can't find the Self-Resonant Frequency in datasheet
Most of the datasheet only have the condiction as shown below
or it mean the test frequency <= Self-Resonant Frequency
You are apparently talking about a common mode choke. A resonance frequency can be well seen in the impedance curve. The choke is useful up to 500 MHz or with reduced performance, 1 GHz. 1 MHz fundamental switching frequency isn't strongly attenuated, depending on the connected circuit impedance.
If you possibly intend to use the common mode choke as flyback inductor, it's not designed for this purpose and would perform poorly.