Speaking during a meeting of his Justice and Development (AK) Party in Ankara, Yildirim said the draft would be presented to lawmakers "in the forthcoming days".
"We are almost ready in our preparations on a new constitutional draft," said Yildirim. "We will seek further common ground with opposition parties."
Yildirim said the nation would have "the final say" on a new constitution.
The ruling AK Party has sought to introduce a presidential system to replace the current parliamentary model since President Recep Tayyip Erdogan became the first head of state elected by popular vote in August 2014.
In order to secure a referendum, it has reached an agreement with the opposition Nationalist Movement Party to give it the necessary 330 votes in parliament.
Yildirim praises Pakistan’s stance against terrorism
In his speech, Yildirim also praised the Pakistani government’s stance against terrorism, ahead of President Erdogan’s two-day visit to Pakistan starting later today.
"We appreciate Pakistan's stance against terrorism. Any country can defeat terrorism or keep a distance from it, if they put their mind to it," Yildirim said.
"Today terrorism is the biggest threat to peace and stability in the world. Terror groups may not directly target some countries but if you don't take necessary measures, no country can be safe."
More than 100 teachers at schools in Pakistan said to be linked to the Fetullah Terrorist Organization (FETO) have been told to leave the country, according to a document seen by Anadolu Agency.
In a notification from the Interior Ministry to Fesih Celik, CEO of the Pak-Turk Education Foundation, the teachers are told their visas will not be extended and they are ordered to leave by Nov. 20.
Turkey has requested that Pakistan close dozens of schools, colleges, and businesses it says are part of the FETO network. The group is accused of orchestrating the July 15 coup attempt in Turkey, which resulted in the deaths of 246 people and the injury of some 2,200 others.
The PakTurk foundation is said to operate 28 schools across Pakistan.