If I create a csv with some indicators from 2007, f.i. ADX(15), I got the identical ADX(15) value at the first 69 data(20170105-20170411).

But if I create the csv from 2006, the ADX(15) in the above time period varied normally.

How can I get the correct indicator value from the very beginning of the defined time period?

Many thanks.

Not at all. Almost all indicators need lookback history for outputting a value.

Oh, LookBack is set for skipping the miscalculation period from the beginning.

I used to think LookBack is to give enough price history for indicator calculation, so the indicator value would be right from the StartDate.

Is my understanding correct this time?

When you gave a real start date, not a file number, then yes.