Not very much. According to Blount, Deism believes that there exists one supreme God,
who is chiefly to be worshipped;
that the principal part of such worship consists in piety and virtue;
that we must repent of our sins and that, if we do so, God will pardon us;
that there are rewards for good men and punishments for evil men both here and hereafter.
On the other hand, Christianity is a supernatural religion and the only absolute one; in a sense, the oldest, for the Church is not an afterthought, but instituted by God in the fullness of time, and containing a revelation of Himself, which all to whom it has been adequately presented are bound under pain of eternal loss to accept (Mark, xvi, 16), offering to all, who are sincere in seeking, the solution of all the world's problems; enabling human nature to rise to the sublimest heights and "to play the immortal"; full itself of mysteries and Divine paradoxes, as bringing the Infinite into contact with the finite; the one bond of civilization, the one condition of progress, the one hope of humanity. Its fortunes have been the fortunes of its Founder; "not all obey the gospel" (Rom., x, 16). The Jews rejected Christ in spite of the evidence of prophecy and miracle; the world rejects the Church of Christ, the "city set upon a hill", conspicuous though she be through the notes that proclaim her Divine. What men call the failure of Christianity is no proof that it is not God's final revelation. It only makes evident how real is human liberty and how grave human responsibility. Christianity is furnished with all the necessary evidence to create conviction of its truth, given goodwill. - "He that hath ears to hear, let him hear".
Peace and blessings!