How to determine parasitic capacitance of a diode according to the datasheet?
"How to determine parasitic capacitance of a diode according to the datasheet?"

There are two simple answers.

1) Read the data sheet and take the value you see . In the case of the data sheet you link, it is stated as being 12 pF.

2) Unless the data sheet provides a graph, you can't.

In general, reverse-biased diodes show a capacitance which decreases with applied voltage. Note that the data sheet you linked only specifies 12 pF at 2000 volts. At 200 volts the capacitance will be a good deal greater. This effect is different for different diode impurity profiles. For instance, tuneable RF circuits will often use varicaps, whose construction is chosen specifically to permit large capacitance variations with applied voltage. Another good example is silicon photodiodes, whose capacitance varies with bias voltage. Since such capacitance affects circuit stability in transimpedance amplifiers, photodiode data sheets typically do provide a capacitance vs reverse voltage graph.