No, they accept all the six Darshanas including Vedanta.
You can read their commentary/explanation on Brahma Sutra here. Though Swami Dayananda Saraswati rejects the interpretation of Brahma Sutras by Adi Shankaracharya and insists on Baudhayana Vritti instead. Read introduction for more information.
Linked text above is in Hindi. Quoting English text from Satyartha Prakasha, a book written by Swami Dayananda Saraswati, the founder of Aarya Samaja: Chapter 3, the scheme of studies
Then they should study the six Shaastraas (commonly called the six schools or systems of philosophy) with the expositions of Rishis - the enlightened great souls, the true seers of nature - as far as possible, or in the absence of these, with the help of the true commentaries of other honest scholars. But before taking up Vedant Shaastraa They should learn the ten Upnishads.** All these books should be finished in two years.
Also check the list of books they approved and books they condemned.