Abstract: A single-array hot wire device for preparing diamond films in a vertical layout belongs to the field of coating technology, and particularly relates to a hot wire device for preparing diamond films. The device includes an upper wall plate of vacuum chamber and a lower wall plate of vacuum chamber, characterized in that: the upper electrode plate is fixedly connected to the upper wall plate of vacuum chamber; a single array of hot wires is vertically distributed, the upper end of which is fixedly connected to the upper electrode plate and the lower end of which is fixedly connected to the lower electrode plate; the lower end of the lower electrode plate is fixed to the hot wire adjusting mechanism, and the hot wire adjusting mechanism is fixed to the lower wall plate of vacuum chamber. The invention uses a single array of hot wires vertically distributed, which can coat a large area on both sides and reduce the cost of hot wires. The vertical distribution of hot wires ensures that the specimen can be removed without destroying the hot wires, which further reduces the cost of hot wires, and the hot wire regulating mechanism at the lower end of the hot wires can tension the hot wires and limit the oscillation of the hot wires to achieve uniform coating.