This's is an Arabic Calligraphy (Thuluth Script)
As it is said: Ammar Youzbashi

In Thuluth, one-third of each letter slopes, from which the name (meaning "a third" in Arabic) comes. An alternative theory to the meaning is that the smallest width of the letter is one third of the widest part. It is an elegant, cursive script. Various calligraphic styles evolved from Thuluth through slight changes of form.