London-based Syrian Network for Human Rights (SNHR) said in December 2017 alone two reporters were killed and four others were arrested.
The report said the Assad regime forces killed 17 media activists, Daesh killed 10 and the Russian forces killed four.
Among the injured, 29 were attacked by the regime forces.
During the year, 93 cases of arrests, abductions and release were recorded.
Daesh-linked Tahrir al Sham was involved in 19 cases of arrests, of which 18 were released.
The Assad regime arrested six and 11 others were arrested by terror groups including the PKK/PYD.
The report added: "Serious quick steps must be taken to save media activism in Syria."
It condemned all violations against media activism regardless of the perpetrators.
It called on the Independent International Commission of Inquiry to conduct investigations on the targeting of media activists.
The report urged Russia as a guarantor state to "apply serious pressure" on its "Syrian and Iranian allies" to comply with the de-escalation agreements.
Syria has only just begun to emerge from a devastating civil war that began in early 2011 when the Assad regime cracked down on pro-democracy protests with unexpected ferocity.