import subscriber from excel file

Jetpack doesn’t allow you to import subscribers at the moment.

To make it easy for your existing users to subscribe again using Jetpack Subscriptions, I would suggest the following:

1. Create a new Page on your site, named “Subscribe”
2. Insert the following shortcode in the page content:
3. [jetpack_subscription_form]
4. Send a link to that page to all these users, to allow them to subscribe using Jetpack Subscriptions.

Another alternative would be to use a different newsletter service, like Mailchimp, that will allow you to import subscriber lists, and to send them all emails.
https://mailchimp.com/

can i do import using curl

so execute that page and send email as post parameter ( in for loop)

You can submit email addresses to the form yourself, but each person will then receive an email asking them to confirm their subscription. Since they didn’t fill in the form themselves, it’s more than likely that a few of them will choose to ignore the confirmation email, or delete it.

I would consequently recommend that you invite your existing mailing list to subscribe by pointing them to a link on your site, while explaining them why they should subscribe.

I hope this clarifies things a bit.