MATLAB: What is the tranfer function of this model

pidSimulink Control Design

how i can know transfer function for this simulink model? i get this simulink model in sltank

You need to be more specific. What transfer function do you want - the plant transfer function:

or the closed loop transfer function:

or some other transfer function?

If you want plant transfer function, define linearization input output points, and use Linear Analysis Tool:

Export the compensator you designed, C, to MATLAB workspace. Then in MATLAB type

C=pid(C)

This will convert the compensator from a transfer function to a PID object. You can then access the gains as shown below.