I can’t try demo version because Dorico not running at my iMac with Sierra as well as MacBook Air with Sierra. Icon of Dorico just disappears from dock panel after starting and that’s all. 
Help me to fix this problem please.
I’m sorry to hear you’re having problems getting up and running. You might find this previous thread helpful. Did you install Dorico in an unusual location?
Can you attach (in a zip file) the crash logs produced by Dorico? You’ll find them in /Users/your-user-name/Library/Logs/DiagnosticReports.